Glass sheet incorporating a plurality of optical elements and method for manufacturing the same

ABSTRACT

To provide a glass sheet incorporating a plurality of optical elements, which incorporates a plurality of glass optical elements and realizes higher productivity and uniform quality of glass optical elements. The glass sheet incorporating a plurality of optical elements includes a plurality of lens parts formed by molding a glass material, reference surface areas each of which is formed around an outer periphery of each lens part and is horizontal to the lens part, and connection parts each of which extends from one reference surface area and connects one lens part to another lens part, in which the connection part has a margin for facilitating separation of the glass sheet into a plurality of pieces.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a glass sheet incorporating aplurality of glass optical elements intended for improvingmass-productivity of glass optical elements used in image sensor chips,such as CCD and CMOS.

[0003] 2. Description of the Related Art

[0004] A conventional glass optical element, for example, a microlenshas been manufactured one by one by melting or softening a sphericalglass material (glass perform) 100′ and press-molding the molten andsoftened glass material in a mold having a molding surface conforming toan optical surface of a lens which is to be manufactured (see FIG. 1).

[0005] For use, a lens 100 thus manufactured has been incorporated intoa lens barrel 101 or the like and combined with an image sensor chip 102as shown in FIG. 2.

[0006] However, according to such a conventional method formanufacturing a microlens, the microlenses 100 are manufacturedseparately one by one. Thus, the productivity is low, and themass-productivity is also disadvantageously low.

SUMMARY OF THE INVENTION

[0007] Thus, an object of the present invention is to provide a glasssheet incorporating a plurality of optical elements, which incorporatesa plurality of glass optical elements and realizes higher productivityand uniform quality of glass optical elements.

[0008] To attain the above-described object, the present inventionprovides a glass sheet incorporating a plurality of optical elementscomprising a plurality of lens parts formed by molding a glass material,reference surface areas each of which is formed around an outerperiphery of each lens part and is horizontal to the lens part, andconnection parts each of which extends from one reference surface areaand connects one lens part to another lens part, in which the connectionpart has a margin for facilitating separation of the glass sheet into aplurality of pieces.

[0009] Furthermore, a mold comprising a upper die and a lower die isused, and the molten and softened glass material is sandwiched andhot-pressed between the upper die and the lower die, therebymanufacturing the glass sheet incorporating a plurality of opticalelements described above.

[0010] Furthermore, according to this invention, a plurality of glassoptical elements can be manufactured in one molding process, andtherefore, the productivity of the glass optical elements is enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 shows a mold for a microlens according to the related art;

[0012]FIG. 2 shows a glass optical element combined with an image sensorchip;

[0013]FIG. 3 is a partial cross sectional view of a glass sheetincorporating a plurality of optical elements according to an embodimentof the invention;

[0014]FIG. 4 is a plan view of the glass sheet incorporating a pluralityof optical elements according to the embodiment of the invention;

[0015]FIG. 5 is a perspective view of an exemplary mold for the glasssheet incorporating a plurality of optical elements; and

[0016]FIG. 6 is a cross sectional view of the glass sheet beingpress-molded.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Now, a preferred embodiment of the invention will be describedwith reference to the drawings.

[0018]FIGS. 3 and 4 show a glass sheet incorporating a plurality ofoptical elements according to this embodiment of the invention.

[0019]FIG. 3 is a cross sectional view of a part of a glass sheet 10incorporating a plurality of optical elements. This glass sheet 10incorporating a plurality of optical elements comprises a plurality oflens parts 1, reference surface areas 2 each of which is formed aroundan outer periphery of each lens part 1 and is horizontal to the lenspart 1, and connection parts 3 each of which extends from one referencesurface area 2 and connects one lens part 1 to another lens part 1. Theconnection part 3 has a margin 4 formed therein to facilitate separationof the glass sheet 10 into a plurality of pieces.

[0020] The lens part 1, the reference surface part 2 and the connectionpart 3 are formed by press-molding a sheet of a glass material. In theembodiment shown in FIG. 3, a cut line 4A is formed on the upper surfaceof the margin 4 so that the cut line 4A separates the lens parts 1 oneby one. However, according to the application, for example, in the casewhere two, three or more lens parts are used as a unit, the areas wherethe cut lines 4A are formed may be varied.

[0021] The cut line 4A may be formed on the lower surface of the margin4 or on both the upper and lower surfaces.

[0022] The reference surface area 2 is formed in the form of a circle inthe lower surface of the outer periphery of the lens part 1, and thereference surface area 2 is horizontal to the lens part 1 and smoothlyconnected thereto. In the smooth reference surface area 2, a circularand recessed adhesive reservoir 5 surrounding the lens part 1 is formed.

[0023] The adhesive reservoir 5 is intended to prevent an adhesive fromexcessively entering to the lens part 1 in the case where the adhesiveis applied to the reference surface area 2 to fix the reference surfacearea 2 and a lens barrel 101 to each other when the glass opticalelement 10A cut from the glass sheet 10 incorporating a plurality ofoptical elements is incorporated with the lens barrel 101, and the glassoptical element and the lens barrel are combined with an image sensorchip or the like (see FIG. 6).

[0024] At least the lens part 1 and the reference surface area 2 arepreferably formed by means of a mold with a highly precise transfersurface.

[0025] In the case where the glass sheet 10 incorporating a plurality ofoptical elements is separated into a plurality of pieces, therebyproviding the glass optical elements 10A having at least one lens part1, and the glass optical element 10A is combined with a device, forexample, an image sensor chip such as CCD and CMOS, to provide anoptical component, the glass optical element 10A which is incorporatedwith the lens barrel 101 is held at the reference surface area 2, andtherefore, the precision of the reference surface area 2 affects thepositional precision of the lens part 1, for example, an inclination ofoptical axis and a focal point.

[0026] Therefore, the reference surface area 2 formed around the outerperiphery of the lens part 1, as well as the lens part 1 itself,requires high precision.

[0027] Thus, the inclination of the optical axis of the lens part 1 withrespect to the reference surface area 2 is preferably 0.05 degrees orless. Furthermore, the amount of misalignment between the center of thereference surface area 2 formed in the shape of a circle around theouter periphery of the lens part 1 (or the center of the outer peripheryof the lens part 1) and the optical axis of the lens part 1 ispreferably equal to or less than 0.02 mm.

[0028]FIG. 4 is a plan view of the entire glass sheet 10 incorporating aplurality of optical elements. In this embodiment, a plurality of lensparts 1 is arranged at regular intervals in longitudinal and lateraldirections. Around the outer periphery of each of the lens parts 1, thereference surface area 2 is formed. The connection part 3, which isformed around the outer periphery of each reference surface area 2 toconnect one lens part to another, has a margin 4 for facilitatingseparation of the lens part 1 from others, and a cut line 4A is formedin the area of the margin 4. That is, the glass sheet 10 incorporating aplurality of optical elements has 8 rows of glass optical elements 10A,each row having 8 glass optical elements 10A.

[0029] A plurality of lens parts 1 formed in the glass sheet 10incorporating a plurality of optical elements are not necessarily formedat regular intervals. According to the application, for example, in thecase where two, three or more lens parts are used as a unit, the lensparts constituting one glass optical element 10A may be arranged closerto each other.

[0030] In order to cut, along the cut lines 4A, the glass sheet 10incorporating a plurality of optical elements into a plurality of glassoptical elements 10A, a positioning mark 6 is formed for positioning ofthe glass sheet 10 incorporating a plurality of optical elements. In theembodiment shown in FIG. 4, two positioning marks 6 are provided on oneside of the rectangular glass sheet 10 incorporating a plurality ofoptical elements, and one positioning mark 6 is provided on one of twosides that intersect with the side.

[0031] The three positioning marks 6 allow the lens parts 1 formed inthe glass sheet 10 incorporating a plurality of optical elements to beaccurately aligned with each other. Thus, when the glass sheet 10incorporating a plurality of optical elements is placed on a cutter forseparation into a plurality of pieces, it can be cut accurately at thearea of the margin 4 (along the cut line 4A) without any damage to thelens part 1.

[0032] Now, a method for manufacturing a glass sheet incorporating aplurality of optical elements will be described with reference to FIGS.5 and 6.

[0033] In this embodiment, a mold comprising at least a upper die and alower die is used, and a sheet of molten and softened glass material ishot-pressed by the upper die and the lower die, thereby manufacturingthe glass sheet 10 incorporating a plurality of optical elements shownin FIG. 3.

[0034] The mold used in this embodiment is shown in FIG. 5.

[0035] In the mold shown in FIG. 5, an upper die unit 20 comprising anupper core 21 having a transfer surface 21A for shaping one of opticallyfunctional surfaces (lens surfaces) of the lens part 1 and an upper mainbody 22 that is to house the upper core and has a transfer surface 22Afor shaping the connection part 3 serves as the upper die, and a lowerdie unit 30 comprising a lower core 31 having a transfer surface 31A forshaping the other of the optically functional surfaces (lens surfaces)of the lens part 1 and the reference surface area 2 and a lower mainbody 32 that is to house the lower core 31 and has a transfer surface32A for shaping the connection part 3 serves as the lower die.

[0036] The upper main body 22 of the upper die unit 20 has a pluralityof mold holes 23, and the upper core 21 is housed in each of the moldholes 23. The lower main body 32 comprising the lower die unit 30 alsohas a plurality of mold holes 33 formed at locations corresponding tothose formed in the upper die unit 20, and the lower core 31 is housedin each of the mold holes 33. In the exemplary mold shown in FIG. 5, theupper main body 22 and lower main body 32 are used which have the moldholes formed at regular intervals.

[0037]FIG. 6 is a cross sectional view of the lens part 1 beingpress-molded. A sheet 10′ of a molten and softened glass material isinserted and hot-pressed between the upper core 21 housed in the moldhole 23 of the upper main body 22 and the lower core 31 housed in themold hole 33 of the lower main body 32, whereby the lens part 1 and thereference surface area 2 are formed on the glass material sheet 10′.

[0038] Preferably, the transfer surface 21A of the upper core 21 and thetransfer surface 31A of the lower core 31 for shaping the lens part 1and the reference surface area 2 are provided with a high precision soas to allow the glass sheet 10 incorporating a plurality of opticalelements having highly precise lens parts 1 and reference surface areas2 to be manufactured.

[0039] In this embodiment, the transfer surface 31A of the lower core 31further has a protrusion for forming an adhesive reservoir 5 in thereference surface area 2 formed in the shape of a circle in the lowersurface of the outer periphery of the lens part 1.

[0040] The connection part 3 is formed by hot-pressing the sheet 10′ ofthe molten and softened glass material between the upper main body 22and the lower main body 32. In FIG. 6, in order to form a cut line 4A inthe margin 4 provided in the connection part 3, the transfer surface 22Aof the upper main body 22 has a protrusion for forming a cut line.

[0041] That is, the molten and softened glass material 10′ is placedbetween the upper die unit 20 and the lower die unit 30, and then, theglass material 10′ is sandwiched and hot-pressed between the upper dieunit 20 and the lower die unit 30, thereby forming a sheet materialincorporating a plurality of glass optical elements 10A shown in FIG. 3(glass sheet 10 incorporating a plurality of optical elements). Then,after cooling the sheet, the upper die and the lower die are opened totake out the molded product.

[0042] The glass material used may be a glass material composed of SiO₂,an alkaline oxide and an alkaline-earth oxide or other various opticalglass materials.

What is claimed is:
 1. A glass sheet incorporating a plurality ofoptical elements, comprising: a plurality of lens parts formed bymolding a glass material; reference surface areas each of which isformed around an outer periphery of each lens part and is horizontal tosaid lens part; and connection parts each of which extends from saidreference surface area and connects one lens part to another lens part,wherein said connection part has a margin for facilitating separation ofthe glass sheet into a plurality of pieces.
 2. The glass sheetincorporating a plurality of optical elements according to claim 1,wherein an angle of inclination of an optical axis of the lens part withrespect to said reference surface area is equal to or less than 0.05degrees.
 3. The glass sheet incorporating a plurality of opticalelements according to claim 1, wherein a cut line is formed in theregion of said margin.
 4. The glass sheet incorporating a plurality ofoptical elements according to claim 1, wherein an adhesive reservoir isformed in said reference surface area to prevent an adhesive for fixingsaid reference surface area and a lens barrel to each other fromentering to the lens part.
 5. The glass sheet incorporating a pluralityof optical elements according to claim 1, wherein a positioning mark isprovided for aligning a plurality of lens parts when the glass sheetincorporating said plurality of lens parts is to be separated into aplurality of pieces.
 6. The glass sheet incorporating a plurality ofoptical elements according to claim 1, wherein the glass sheet is formedby press-molding a sheet of a glass material.
 7. A method formanufacturing a glass sheet incorporating a plurality of opticalelements, wherein a molten and softened glass material is placed betweena upper die and a lower die, and the glass material is sandwiched andhot-pressed between said upper die and said lower die, thereby forming asheet material incorporating a plurality of glass optical elementshaving a plurality of lens parts, reference surface areas each of whichis formed around an outer periphery of each lens part and is horizontalto the lens part, and connection parts each of which extends from saidreference surface area and connects one lens part to another lens part,said connection part having a margin for facilitating separation of theglass sheet into a plurality of pieces, and after cooling, the upper dieand the lower die are opened to take out the molded product.
 8. Themethod for manufacturing a glass sheet incorporating a plurality ofoptical elements according to claim 7, wherein an upper die unitcomprising an upper core having a transfer surface for shaping one ofoptically functional surfaces of the lens part and an upper main bodythat is to house the upper core and shape the connection part serves asthe upper die, and a lower die unit comprising a lower core having atransfer surface for shaping the other of the optically functionalsurfaces of the lens part and the reference surface area and a lowermain body that is to house the lower core and has a transfer surface forshaping the connection part serves as the lower die.
 9. The method formanufacturing a glass sheet incorporating a plurality of opticalelements according to claim 7 or 8, wherein a sheet of a molten andsoftened glass material is hot-pressed.